Surface tension and alveolar changes during ventilation

Abstract

The clinical experience of the last 20 years has amply demonstrated the importance of acute pulmonary failure and the need for respiratory support in critically ill patients [8, 43, 44]. The importance of pulmonary failure and respiratory care have been emphasized even when the patient’s primary disease does not originate in the lungs. This became apparent to me over 15 years ago while working in a clinical research unit at the Walter Reed Army Hospital. Although the indication for patient admission to this unit was hemodynamic failure (shock), 3/4 of the patients required mechanical ventilatory support, and a direct correlation between severity of pulmonary failure and mortality was demonstrated [7]. Further clinical research activities by United States Military Medical teams functioning in forward hospitals during the Viet Nam conflict confirmed the importance of pulmonary failure in patients suffering major trauma even when the lung was not directly injured [51, 52]. The result of numerous clinical observations such as these provided a powerful impetus to the laboratory study of normal lung function and the impact of disease on the lung. Much has been learned at the bedside and in the laboratory; and as a result the pulmonary care of acutely and critically ill patients has been immensely improved. On the other hand, it may be argued that one of the most important things we have learned both in the laboratory and at the bedside is the depth of our ignorance.